GSM/GPRS/NB-IoT Module Series
BC68&M66 Compatible Design
BC68&M66_Compatible_Design 15 / 31
BC68/M66 Module
VBAT
C1
100uF
+
C2
100nF
C3
33pF
C4
10pF
D1
VBAT
Figure 3: Reference Circuit of VBAT
4.2. Power-on Circuit
The turn-on method of BC68 is different from M66. BC68 can be powered on automatically when VBAT
pins are powered. M66 will be powered on by driving the pin PWRKEY to a low level voltage for more than
100ms, and an open collector driver circuit is suggested to control the PWRKEY. The following is a
reference design for power-on circuit of M66.
Turn on pulse
PWRKEY
4.7K
47K
≥ 100ms
Figure 4: Driving Circuit of the PWRKEY